For purposes of this disclosure, the term "materials", "contaminants" and "particulates" as used herein should be understood to mean any dispersible hazardous, toxic, or nuisance matter which can be organic or inorganic, or admixtures adsorbed or sorbed upon each otter. These materials, contaminants and particulates are generally low-weight pieces of larger materials that have fractured or otherwise been broken down and tend to be less than 5-10 microns in size and disperse in the air with shifting air currents, thereby causing their removal from the atmosphere to be particularly difficult. The particulates may also be in the form of dust particles formed in the processing of larger materials. The materials may also be of larger particle size and less likely to become dispersed in the air.
The safe removal, transport and eventual disposal of hazardous, toxic and nuisance materials has become of particular importance in this age of concern for the environment. To this end, many federal, state and even local regulations have been enacted that first identify, then seek to regulate, the handling of potentially hazardous materials. A number of these regulations concern the handling and disposal of asbestos, a known carcinogen.
The Environmental Protection Agency (EPA) and Occupational Health and Safety Agency (OSHA) have major responsibility for regulatory control over exposure to asbestos. Emissions of asbestos to the ambient air are regulated under Section 112 of the Clean Air Act, which establishes the National Emission Standards for Hazardous Air Pollutants (NESHAPs). The regulations specify control requirements for most asbestos emissions, including work practices to be followed to minimize the lease of asbestos fibers during handling of asbestos waste materials. For example, section 177.844 of the EPA's "Hazardous Materials Guide" requires that "Asbestos must be loaded, handled, and unloaded, and any asbestos contamination of transport vehicles removed, in a manner that will minimize occupational exposure to airborne asbestos particles released incident to transportation."
The regulatory interest in asbestos and other hazardous wastes has also spawned a number of patents directed to the removal, handling and eventual disposal of these contaminants. These patents, among other things, are directed to the removal of asbestos, the filtration of the air in which the removal is taking place, and the eventual disposal of the asbestos. In particular, many of the patents are directed to problems in dealing with asbestos and other contaminants because of their extremely small particle size. For example, it has been found that the average asbestos fiber is about 0.1 micron in diameter and less than 5 microns in length; this small size and corresponding low weight resulting in many of the asbestos fibers easily becoming airborne with shifting air currents.
While much attention has been given to controlling the environment where the asbestos removal is taking place, and to disposal of the contaminants, insufficient regard has been given to the actual handling and transport of the asbestos once it has been removed. The result is that the controls that exist with respect to removal and eventual disposal are being circumvented.
Existing methods of containing and handling hazardous materials, particularly asbestos, which takes place in a controlled chamber, comprises packaging of the particulates, then loading and transport of these packages in various forms of transportable containment vessels, has fallen short of protecting the outside environment from the potential and real danger these contaminants produce. The current practice is to rely on the package itself when in fact it is well known in the containment and transport industry that the controlled chambers may not be adequately connected to the transport apparatus to prevent accidental release of contaminants and that workers sometimes use defective and damaged packaging materials, and otherwise exercise practices that risk release of the contaminants to the outside atmosphere.
Systems that rely on extending the controlled chamber from the contaminated site to the transport containment vessel are known, such as in U.S. Pat. No. 4,774,974 to Teter, however, such systems may be of limited utility. It is common industry practice that asbestos and other hazardous waste removal take place in a site that has been modified by the addition of some sort of enclosure to prevent the accidental release of the contaminants to the unprotected air, i.e., a controlled chamber. Controlled chambers are expensive, however, particularly when it is common practice to extend them to encompass the containment vessel that is to transport the removed contaminants. In other words, the transportable containment vessel is essentially part of the controlled chamber during the removal and loading operation.
The present system for handling contaminants is not, however, very practical. For example, much of the asbestos removal that takes place in major cities involves older multistory facilities that cannot be readily accessed from where the known containment vessels would have to be situated. Further, it is often the case that the asbestos is only being removed from selected parts of a structure, while other parts are still in use, thereby requiring that the removal system be as non-disruptive as possible. In addition, the known systems require that the unit be present at all times during asbestos removal, thereby necessitating a separate, expensive unit at each work site.
It is common industry practice that after the asbestos or other hazardous particulate is removed from the walls, ceilings and other parts of a structure, the particulate is encased in bags which may be readily moved and eventually disposed of. Such bagging practice also enjoys significantly reduced costs, which makes it all the more attractive to practitioners of asbestos and other hazardous waste removal.
Various forms of bags are used to enclose the particulate prior to its eventual disposal. As exemplified in U.S. Pat. Nos. 4,229,193; 4,626,291; 4,7I8,925; 4,726,825; 4,746,175; 4,749,391; 4,765,352; and 4,783,129, the filling of the bags commonly is accomplished in the controlled chamber where the contaminant is located. The bags are then handled and moved from the controlled chamber and cut to the apparatus to be loaded and used to transport this material to the waste disposal site. Careful procedures are used to remove and bag the material, however, airborne micro particulates within the removal site may attach to the exterior surface of the bags and protective suits worn by the workers.
The result of such a procedure is that contamination of the environment may be occurring in a number of ways. First, as the workers leave the controlled chamber while handling the bags of contaminant, the particulate that has clung to the outside of their protective garb and isolating bags may be released. This release occurs between the controlled chamber where removal is occurring and the transport apparatus. Accordingly, the protection afforded by the controlled chamber is being circumvented.
The second manner of potential contamination involves the manner in which the bags are loaded into the cargo chambers of vehicles for transport to disposal sites. These vehicles, while designed for general freight use, are relatively incapable of environmentally controlling the containment vessel. The bags of particulate are generally loaded from the front, opposite the access door, to the rear of the vehicle, and stacked upon themselves as high as the chamber height will allow. It should be noted that the bags of particulate may be quite heavy, as it is often the case that the particulate is wetted down during the removal and bagging process. The weight of the bags stacked on top causes compression of the lower bags which may result in the release of any entrapped air from within the bags via either where the bag has been sealed, such as by tape or twist-ties, or cause the bursting of the bags. The result of such accidental release is that macro and micro-sized particulates escape the bags into the environment of the containment vessel, and eventually the atmosphere.
Alternatively, and less desirably, the controlled chamber in which removal is taking place is extended to encompass the transport apparatus. This may occur by sealing the transport vehicle to the control chamber or as in U.S. Pat. No. 4,774,974, discussed above, by running tubes from the transport apparatus to the control chamber. Such extension is substantially equivalent to connecting the control chamber and transport apparatus by virtue of a seal.
In addition, it is well known in the waste transportation industry that freight may be damaged during handling and transport. Damage in handling may result from, among other things, the excessive weight of the bags of particulate or from improper bag sealing procedures. As for damage in transport, it is not uncommon in transporting general freight to see broken cartons, boxes, skids and even protective crates resulting from damage incurred from loading, transporting or unloading. Hazardous waste transportation is no exception and current packaging methods, i.e. bags, lend themselves to breakage, once again providing a clear path for material escape.
Further, it is known that the interiors of transport vehicle containment chambers are generally hotter than the outside ambient temperature. The principles of heat transfer cause a natural flow of air to occur within the chamber through any available apertures in an outward direction toward the cooler surrounding environment. This convection, if not controlled, results in a constant outward leakage of air, thus amplifying material escape.
Once material release has occurred, in any or all of the above described methods, the micro-sized particulates may become air borne freely exposing the surrounding unprotected environment to contamination. It is therefore necessary to control the flow of material leakage between the controlled chamber and the cargo chamber and within the confinement of the cargo chamber, whether the cargo chamber's access portal is opened or closed, during loading and unloading, and in temperate as well as adverse climatic conditions.
Current contaminant transportation apparatus are clearly not providing the containment controls necessary in common hazardous waste abatement operations. This has created a void between the removal procedure and the disposal site exposing human life to the same threat that the removal and disposal procedures were employed to prevent.